The commercial construction industry has long experienced a variety of accidents wherein workmen and equipment exit or enter an area where there is danger. With regard to the roofing industry, given the frequency with which workmen must work and operate machinery in a rooftop setting, falls from the roof edges occur in a variety of somewhat predictable circumstances. One recurring circumstance which gives rise to roof top falls is that of workmen who inadvertently lose track of their proximity to a roof edge while working. They may stray toward a roof edge without being aware of it due to their concentration on the task at hand or due to the very manner in which they must move, including backing up, as they carry out roofing tasks. Another recurring circumstance giving rise to roof top falls is when a workman is involved in the operation of a piece of roofing equipment. In such circumstances, the workman often does not see the area in front of the equipment or may take his vision from the path along which he is travelling as he monitors or operates the equipment. This may lead to the equipment moving over the edge of a roof leading to an unexpected event which may also place the operator of the equipment in danger of falling from the roof.
Historically the roofing industry has attempted to minimize the occurrence of circumstances in which a workman is placed dangerously close to a roof edge by adopting a variety of safety regulations pertaining to roof top work. These include various regulations, including those promulgated by the Occupational Safety and Health Administration (OSHA) and adopted by most states. These regulations require that a variety of warning lines, personnel monitoring procedures, and perimeter guard rails be used near roof edges to prevent falls.
Traditional perimeter warning systems and barriers have a variety of shortcomings. First, the personnel monitoring systems rely upon human observation to warn workers of roof edge dangers. These are susceptible to failure by the mere fact that humans make mistakes. Secondly, the warning line systems are bulky in that they require a large number of upright stanchions, with heavy weighted bottoms, to surround the perimeter of a large commercial roofing project. Thus, a large amount of weight must be taken to the roof top and placed along a large perimeter. This is labor intensive and time consuming. In addition such systems, typically using a flexible line between stanchions, are prone to failure if the line is too slack or the workman does not sense the feel of the line, or it is impacted by equipment which does not sense its presence. In a third instance, rigid guard rails are utilized with very heavy base plates. These are designed to resist toppling by a falling person. By their very nature such systems are heavy, difficult and time consuming to emplace on a roof and are extremely expensive.
For all of the forgoing reasons, there has evolved in the commercial roofing industry an environment in which perimeter warning systems are not put in place when regulation requires that they be used. As a result, the incidence of falls and injuries increases. The present invention avoids these calamitous results by providing an inexpensive, effective and very portable electronic warning system with which to guard the perimeters of roofs upon which work is being undertaken.